The goal of this SCOO program is provide the scientific basis for the prevention of fibrotic and immunologic lung disease which are related to the occupational environment. A multidisciplinary approach is utilized in order to establish causal relationships, dose-response curves, and theshold llvels of exposure in lung disorders which are related to the inhalation of mineral and organic dusts, and chemical vapors and gases. Disciplines incorporated in this Center include pulmonary physiology, epidemiology, biostatistics, immunology, chest roentgenoraphy, bioengineering, environmental chemistery and industrial hygiene. Significant emphasis is placed on newer methods of characterizing the inhaled envionment which should lead to establishment of those methods which relate best to the indexes of an altered biologic response, and therefore most closely estimate the true exposure dose. The overall significance of this program liesin thefact that these ocupational lung disorders are potentially completely preventable, and data from these stuies should lead to the establishment of rational occupational environmental standards for hazardous inhalants.